A Light-Emitting Diode (LED) TV, which has coming to the market, is an LCD TV adopting an LED backlight using white or three primary colors, more accurately an LCD TV using an LED backlight, instead of a Cold Cathode Fluorescent Lamp (CCFL) backlight of an existing LCD TV. As an LED full-color display presently available in the market, an ultra-large full-color outdoor electronic display board into which several ten thousands of three-color LED elements are inserted is known as a unique available product. Therefore, in an accurate conception, an LED full-color display is not yet adopted at the present as a home TV or a computer monitor. An existing LED element is not available as a display having a size of a TV or monitor due to the technical limits in relation to the manufacturing of an LED element and the full-color implementation technique. Presently, for an LED, an III-V group p-n light emitting diode is grown on a substrate of 2 to 8 inches by means of MOCVD and then cut into an appropriate size on which an electrode is wired, and then it is used as a unicolor or white LED element. In order to make a display for TV by using an III-V group wafer, in simple calculation, TV of 40 inches may be produced by attaching 5 to 20 wafers of 2 to 8 inches. In addition, in order to implement full-color with an LED, red-green-blue three-color LED elements should be put into a single pixel, and an LED full-color display may not be implemented by simply joining red-green-blue LED wafers. As another simple method for implementing an LED TV, a red-green-blue film or a nanorod-based LED element may be directly grown on a pixel of a large-area glass substrate for an actual display. However, this problem causes the same problems as when an LED is implemented by growing a high-quality III-V group film on a glass substrate by means of MOCVD. As well known in the art, the MOCVD for growing an III-V group film does not allow direct deposition on a substrate having a TV display size and also does not allow deposition of high-crystallinity and high-efficiency III-V group films or nanorods on a glass substrate. Due to such technical limits, there has not been proposed an effective technique for directly manufacturing a full-color display for a TV of 20 inches or above or a monitor of 14 inches or above by using an LED wafer.
In spite of the limits in manufacturing techniques and realistic possibility, an LED TV must be developed due to low light emission efficiency of an existing LCD display. As known in the art, a full-color TFT-LCD, which is dominating the TV and monitor market at the present, emits just about 5% of the light emitted from a backlight to the front surface. An LCD uses two polarizers during an on/off procedure for penetration/blocking of light, a color filter to converting a white light passing through a liquid crystal into a three-color light, and a plurality of optical films while uniformly dispersing the light generated from a single backlight lamp, which causes an optical attenuation of about 95%. In detail, it is known that a light emission efficiency of a full-color LCD display is 2 to 3 lm/W in case of using a backlight lamp of 60 lm/W. Therefore, in case of an LED-LCD TV using LED as a backlight, even though the efficiency of the LED is greatly improved, there is a limit in improvement of efficiency of an actual display. It is reported that a white LED recently developed already has efficiency of 100 lm/W or above, which is expected to reach 200 lm/W in a few years. Therefore, it will be easily understood that directly manufacturing a full-color display by using high-efficiency LED is the most suitable method in aspect of light emission efficiency, in comparison to manufacturing a display by using high-efficiency LED as the LCD backlight.
Therefore, a technique required for realizing a high-efficiency LED display becomes a main issue of this study. If technical or physical limits are not considered, developing a method for directly manufacturing LED pixels on a large-area display glass substrate will be the path of least resistance, which can be conceived by anyone. However, if the techniques for IIV-V growth are understood just a little, it will be figured out that this cannot be realized by the present techniques. Therefore, it will be reasonable in aspect of light emission efficiency to develop a new structure and technique for manufacturing a full-color LED display by using an existing high-efficiency III-V group LED wafer grown by means of MOCVD. Until now, the LED display manufacture and element techniques have been developed to implement a display by arranging one LED element at one pixel. For example, it has been reported that in case of a recently developed micro-sized LED display, a small micro LED display has been developed by fabricating one pixel with one micro LED. As another example, there is also reported a technique for manufacturing a display of a desired size by fabricating an LED of a micro size on a plastic substrate with great elasticity and then extending the substrate to increase its area. The technique for manufacturing a display in which a single micro LED array corresponds to a single pixel is easy to develop a subminiature micro LED display but has very high technical thresholds to be overcome in order to have a great area suitable for a TV or monitor. Moreover, if several LEDS are poor among several ten thousands of LEDS of the display, the entire display may be poor. Therefore, in order to implement a high efficiency LED display, there is needed a creative and simple structure and technique which may overcome the existing techniques.